The histogram reveals two primary elevation groupings: the continents, several hundred meters above sea level, and the oceanic abyssal plains, roughly 4,300 meters below sea level. This distribution indicates that the crust of the ocean floor is fundamentally different from the continents, which has been confirmed by countless research studies. The dramatic steepening of the hypsographic curve at mountains and oceanic trenches can only be maintained by a dynamic Earth. On geologic timescales, such features would quickly erode or fill in with sediments.

The histogram was determined using Equation 1 to calculate the area of each cell, which were grouped by elevation and summed (Table 1). ETOPO1 elevation values are to the nearest meter, with an accuracy no better than ten meters. In deep ocean areas, depths are accurate to tens of meters at best. The hypsographic curves (Figs. 1 and 2) were smoothed to remove anomalies, and show the proportion of Earth's land and sea floor areas.